The need to have accurate and rapid antibiotic susceptibility techniques is becoming more urgent due to the increased resistance of bacteria to antibiotics. The resistance of bacteria to antibiotics has been referred to by the Centers for Disease Control and Prevention (CDC) as one of the world's most pressing health problems. Currently, out of 2 million people who get infections in the US each year, approximately 90,000 of deaths occur as a result of the bacterial infection and, of these cases, over 70 percent are resistant to one or more antimicrobials.
A developing technique in microbiology, with potential applications to antimicrobial susceptibility measurements, has been the study of cell properties on the single cell level. Performing measurements on a single microbe rather than millions offers the advantage of taking measurements that are obtained on the time scale of cell division. Some microscopy-based single cell techniques appear to be currently suitable for the study of cell growth (Elfwing et al., Applied and Environmental Microbiology, 70(2):675 678, 2004); however, the same technique has not been demonstrated as a sensor that can both detect pathogens and perform antimicrobial susceptibility measurements. Using microscopy techniques alone would be especially difficult, when attempting to detect and optically track the growth of a single bacteria. For example, when the size of the bacterium is small, such as Staphylococcus aureus, the growth would be more difficult to measure with standard microscopy techniques, because of its smaller size and near-spherical shape.
Rapidly determining an antibiotic that would work against an infection would save lives and limit improper antimicrobial therapy. Correctly diagnosing a bacterial infection and measuring its growth and susceptibility to antimicrobials on the time scale that a doctor would prescribe an antimicrobial, would aid in appropriate antimicrobial therapy. Appropriate therapy significantly reduces the risk of death and limits the exposure of resistant bacterial strains to multiple ineffective treatments of antibiotics, reducing the risk of the development of further resistance.
Indeed, the CDC suggests that one of the ways to prevent antimicrobial resistance is simply to properly diagnose and properly treat an infection. The development of new and stronger antibiotics alone will not remedy the dilemma of increasing antimicrobial resistance. Instead, there is a need in the art for both new antimicrobial developments and for applications of technologies that will allow doctors to determine appropriate antimicrobial therapy.